Wearable electronics and photonics are a class of systems with potential to broadly impact a range of technologies, industries and consumer products. Advances in wearable systems are driven, in part, by development of new materials and device architectures providing for new functionalities implemented using device form factors compatible with the body. Wearable consumer products are available, for example, that exploit small and portable electronic and/or photonic systems provided in body mounted form factors, such as systems building off of conventional body worn devices such as eye glasses, wrist bands, foot ware, etc. New device platforms are also under development to extend the range of wearable technology applications including smart textiles and stretchable/flexible electronic systems incorporating advanced electronic and photonic functionality in spatially complaint form factors compatible with low power operation, wireless communication and novel integration schemes for interfacing with the body. [See, e.g., Kim et al., Annu. Rev. Biomed. Eng. 2012.14; 113-128; Windmiller, et al., Electroanalysis; 2013, 25, 1, 29-46; Zeng et al., Adv. Mater., 2014, 26, 5310-5336; Ahn et al., J Phys. D: Appl. Phys., 2012, 45, 103001.]
Tissue mounted systems represent one class of wearable systems supporting diverse applications in healthcare, sensing, motion recognition and communication. Recent advances in epidermal electronics, for example, provide a class of skin-mounted electronic and/or optoelectronic systems provided in physical formats enabling intimate contact with the skin. [See, e.g., US Publication No. 2013/0041235.] Epidermal electronic systems combine high performance stretchable and/or ultrathin functional materials with soft elastic substrates implemented in device geometries useful for establishing and maintaining conformal contact with the soft, curvilinear and time varying surface of the skin. A number of sensing modalities have been demonstrated using this platform including physiological monitoring (e.g., temperature, thermal transport, hydration state, etc.) and transduction of chemical information, for example, in connection with the characterization of bodily fluids (e.g., pH, salt composition, etc.). [See, e.g., Huang et al., Small, 2014, 10 (15) 3083-3090; Gao, et al., Nature Communications, 2014, 5, 4938.]
Despite considerable advances in tissue mounted systems a number of challenges remain in the development of certain applications for this technology. First, conformal integration of these systems on some classes of tissue, such as the epidermis, can adversely impact the physiological state and/or chemical condition of the tissue, for example resulting in unwanted irritation and/or immune response. Tissue mounted systems can also influence the exchange of heat, fluid and/or gas at the mounting site, thereby having the potential to interfere with physiological and chemical characterization of tissue. Further, long term, reliable integration remains a challenge for some tissue types such as tissues characterized by rapid rates of growth, fluid exchange and/or exfoliation.
It will be appreciated from the foregoing that tissue mounted electronic and photonic systems are needed to support the emerging applications in wearable electronics. Tissue mounted systems and methods are needed that are capable of robust and intimate integration without substantial delamination. Tissue mounted systems and methods are needed that are capable of providing good electronic and photonic performance in a manner not adversely impacting the tissue at the mounting site. In addition, tissue mounted systems are needed that are compatible with efficient manufacturing to enable cost effective implementation for a range of applications.